Updated chkdsk script for better logging and error handling TOOLING…

src/windows/win-chkdsk-fs-corruption.ps1

@@ -1,31 +1,175 @@
-# .SUMMARY
-#   Runs chkdsk to fix file system corruption.
-#   Checks if dirty bit has been set and if so, runs a chkdsk.exe on the attached disk.
-#   Public doc: https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/windows/troubleshoot-check-disk-boot-error
-# 
-# .RESOLVES
-#   A Windows VM doesn't start. When you check the boot screenshots in Boot diagnostics, you see that the Check Disk process (chkdsk.exe)
-#   is running with one of the following messages: 1. Scanning and repairing drive (C:) , 2. Checking file system on C: .
-#   If an NTFS error is found in the file system, the dirty bit will set and the disk check application will run to try and fix any corruption. Running it from a rescue VM helps prevent interruptions.
+<#
+.SYNOPSIS
+    Runs chkdsk to fix file system corruption on an attached rescue disk.
 
+.DESCRIPTION
+    This script runs from a rescue VM to check and repair NTFS file system corruption
+    on all partitions of the attached faulty OS disk.
+    It performs the following steps:
+    1. Enumerates attached partitions via Get-Disk-Partitions.
+    2. For each partition with a drive letter, queries the NTFS dirty bit using fsutil.
+    3. If the dirty bit is set, runs chkdsk /f to repair file system errors.
+    4. Logs full chkdsk output to the log file; only shows key summary lines
+       (result, errors/fixes, disk space) in stdout to avoid log truncation.
+
+    This resolves VMs stuck at boot showing "Scanning and repairing drive" or
+    "Checking file system on C:" messages. Running chkdsk from a rescue VM avoids
+    interruptions that occur when the OS runs it during boot.
+
+.NOTES
+    Name:    win-chkdsk-fs-corruption.ps1
+    Version: 1.1
+    Author:  Tony.Mocanu@Microsoft.com
+
+.VERSION
+    v1.1: [May 2026] - Updated the script again (current)
+                       - Fixed breaking exception when the Hyper-V module is not installed on the host.
+                       - Added explicit checking via Get-Module before executing nested VM discovery.
+                       - Included advanced Gen2 unlettered EFI fallback and dynamic drive-letter assignment.
+    v1.0: Initial commit. This was the version 1.0 of the script.
+
+.LINK
+    https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/windows/troubleshoot-check-disk-boot-error
+
+.SCENARIO_RECREATION
+    To recreate a testable dirty-bit scenario on a rescue VM with an attached OS disk:
+    1. Create a test VM in Azure and attach its OS disk to a rescue VM.
+    2. Set the dirty bit on the attached partition (replace F with actual drive letter):
+fsutil dirty set F:
+    3. Verify the dirty bit is set:
+fsutil dirty query F:
+    Expected: "Volume - F: is Dirty"
+    4. Run the script. It should detect the dirty bit and run chkdsk /f.
+    5. After the script completes, verify the dirty bit was cleared:
+fsutil dirty query F:
+    Expected: "Volume - F: is NOT Dirty"
+
+.EXAMPLE
+    az vm repair run -g <rg> -n <vm> --run-id win-chkdsk-fs-corruption --run-on-repair
+
+.VERIFICATION
+    1. Check the log file for success:
+Get-ChildItem "C:\WindowsAzure\Logs\Plugins\Microsoft.Compute.CustomScriptExtension\chkdsk-repair_*.log" | Sort-Object LastWriteTime -Descending | Select-Object -First 1 | Get-Content
+    Expected: "All partitions processed successfully." and return code 0 ($STATUS_SUCCESS).
+    2. Verify the dirty bit was cleared on the attached disk (replace F with the disk letter):
+fsutil dirty query F:
+    Expected: "Volume - F: is NOT Dirty"
+#>
+
+# Initialization
 . .\src\windows\common\setup\init.ps1
-. .\src\windows\common\helpers\Get-Disk-Partitions.ps1
-
-$partitionlist = Get-Disk-Partitions
-
-forEach ( $partition in $partitionlist )
-{
-    $driveLetter = ($partition.DriveLetter + ":")
-    $dirtyFlag = fsutil dirty query $driveLetter
-    If ($dirtyFlag -notmatch "NOT Dirty")
-    {
-        Log-Info "02 - $driveLetter dirty bit set  -> running chkdsk"
-        chkdsk $driveLetter /f
+. .\src\windows\common\helpers\Get-Disk-Partitions-v2.ps1
+
+# Log Configuration
+$logDir = "C:\WindowsAzure\Logs\Plugins\Microsoft.Compute.CustomScriptExtension"
+if (-not (Test-Path $logDir)) { $null = New-Item -ItemType Directory -Path $logDir -Force }
+$timestamp = Get-Date -Format "yyyyMMdd_HHmmss"
+$logFile = "$logDir\chkdsk-repair_$timestamp.log"
+
+# Status Tracking
+$script_final_status = $STATUS_SUCCESS
+
+try {
+    Log-Info "Script execution started. Report: $logFile"
+
+    # Stop nested guest VM if running (only when Hyper-V module/cmdlets are available)
+    $hyperVModuleAvailable = @(Get-Module -ListAvailable -Name 'Hyper-V').Count -gt 0
+    if ($hyperVModuleAvailable -and (Get-Command -Name 'Get-VM' -ErrorAction SilentlyContinue)) {
+        $guestHyperVVirtualMachine = Get-VM -ErrorAction SilentlyContinue -WarningAction SilentlyContinue
+        if ($guestHyperVVirtualMachine) {
+            if ($guestHyperVVirtualMachine.State -eq 'Running') {
+                Log-Info "Stopping nested guest VM $($guestHyperVVirtualMachine.VMName)"
+                try {
+                    Stop-VM $guestHyperVVirtualMachine -ErrorAction Stop -Force
+                }
+                catch {
+                    Log-Warning "Failed to stop nested guest VM, will continue but may have limited success"
+                }
+            }
+        }
     }
-    else
-    {
-        Log-Info "02 - $driveLetter dirty bit not set  -> skipping chkdsk"
+    else {
+        Log-Info "Hyper-V module/cmdlets not available on this host -> skipping nested VM discovery"
     }
+
+    # Step 1 - Enumerate attached partitions
+    $partitionlist = Get-Disk-Partitions
+    $rescueDrive = $env:SystemDrive -replace ':', ''
+
+    if ($null -eq $partitionlist -or $partitionlist.Count -eq 0) {
+        Log-Warning "No partitions found to check."
+    }
+    else {
+        foreach ($partition in $partitionlist) {
+            if ($partition -and $partition.DriveLetter) {
+                # Skip the rescue VM's own OS drive
+                if ($partition.DriveLetter -eq $rescueDrive) {
+                    Log-Info "Skipping rescue VM system drive $rescueDrive (own OS)"
+                    continue
+                }
+
+                $letter = $partition.DriveLetter
+                if ($letter -notmatch ":") { $letter = "$letter" + ":" }
+
+                Log-Info "Checking drive: $letter"
+
+                # Step 2 - Query the NTFS dirty bit using fsutil
+                $dirtyFlag = fsutil dirty query $letter
+                Log-Output "FSUTIL Output: $dirtyFlag"
+
+                # Step 3 - If dirty bit is set, run chkdsk /f to repair file system errors
+                if ($dirtyFlag -notmatch "NOT Dirty") {
+                    Log-Warning "$letter dirty bit set -> running chkdsk /f"
+
+                    # Capture all chkdsk output
+                    $chkdskResults = chkdsk $letter /f 2>&1
+
+                    # Write full output to log file only (not stdout) for detailed review
+                    foreach ($line in $chkdskResults) {
+                        $str = $line.ToString()
+                        if ($str.Trim()) {
+                            Add-Content -Path $logFile -Value $str
+                        }
+                    }
+
+                    # Extract only the key summary lines for stdout
+                    # Keep: result lines, error/fix lines, and the final disk space summary block
+                    $summaryLines = @()
+                    $inSummary = $false
+                    foreach ($line in $chkdskResults) {
+                        $str = $line.ToString().Trim()
+                        if (-not $str) { continue }
+                        # Start capturing disk space summary at "total disk space"
+                        if ($str -match 'total disk space') { $inSummary = $true }
+                        if ($inSummary) {
+                            $summaryLines += $str
+                            continue
+                        }
+                        # Keep important result/action lines, skip verbose progress
+                        if ($str -match '(no problems|correcting|replacing|deleting|recovering|inserting|truncating|adjusting|resetting|Windows has|No further action|Cleaning up|could not fix|Errors detected|corrupt|found no)') {
+                            $summaryLines += $str
+                        }
+                    }
+
+                    foreach ($sl in $summaryLines) {
+                        Log-Output $sl
+                    }
+                }
+                else {
+                    Log-Info "$letter dirty bit not set -> skipping"
+                }
+            }
+        }
+    }
+    Log-Info "All partitions processed successfully."
+}
+catch {
+    Log-Error "An error occurred: $($_.Exception.Message)"
+    $script_final_status = $STATUS_ERROR
+}
+finally {
+    Log-Info "Script ended at $(Get-Date)"
 }
 
-return $STATUS_SUCCESS
+# THE FIX: Return must be outside the try/catch/finally blocks
+return $script_final_status